Compositions comprising at least one friction modifying compound, and methods of use thereof

ABSTRACT

There is disclosed a lubricant composition comprising at least one anionic compound; and at least one cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifier; and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater, and (ii) a passing High Temperature L-37 score.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Patent Application Ser. No. 60/916,893, filed on May 9, 2007, the disclosure of which is incorporated in its entirety by reference herein.

DESCRIPTION OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to a composition comprising an anionic compound, and a cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifier. Also disclosed herein are methods of using the disclosed composition.

2. Background of the Disclosure

Although a substantial number of gear oils have been produced having various properties there exists a need for an additive or a combination of additives to provide at least one of improved antiwear, improved thermal stability, improved oxidative stability, improved fuel efficiency, improved temperature roll over effect, decreased noise, decreased wear, and decreased pitting. In particular, a need exists for an additive that can provide at least one of these properties to a machine, such as a gear, when the gear has not been broken-in for either some time period or for some distance. There is also a need for an additive that can provide at least one of these properties to a gear prior to towing a load.

Finally, a need exists for an additive that can meet at least one of the above-described properties and still meet the industry standards, such as the high temperature variation of ASTM D-6121 (“High Temperature L-37 test”)

SUMMARY OF THE DISCLOSURE

In accordance with the disclosure, there is provided a lubricant composition comprising at least one anionic compound; and at least one anionic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifier; and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater, and (ii) a passing High Temperature L-37 score.

In an aspect, there is also provided a method of making a composition comprising providing at least one anionic compound and at least one cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifying compound comprising from about 10 to about 30 carbon atoms, and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater, and (ii) a passing High Temperature L-37 score.

Additional objects and advantages of the disclosure will be set forth in part in the description which follows, and/or can be learned by practice of the disclosure. The objects and advantages of the disclosure will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the present teachings are exemplified in the accompanying drawings. The teachings are not limited to the embodiments depicted, and include equivalent structures and methods as set forth in the following description and known to those of ordinary skill in the art.

In the drawings,

FIG. 1 is a graph demonstrating the relationship between high fluid temperature (T_(MAX)), end-of-test temperature (T_(EOT)), and the difference between the high temperature and end-of-test temperature (T_(roll over)).

DESCRIPTION OF THE EMBODIMENTS

As used herein, the term “hydrocarbyl”, “hydrocarbyl substituent” or “hydrocarbyl group” is used in its ordinary sense, which is well-known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having predominantly hydrocarbon character. Examples of hydrocarbyl groups include:

(1) hydrocarbon substituents, that is, aliphatic (e.g., alkyl or alkenyl), alicyclic (e.g., cycloalkyl, cycloalkenyl) substituents, and aromatic-, aliphatic-, and alicyclic-substituted aromatic substituents, as well as cyclic substituents wherein the ring is completed through another portion of the molecule (e.g., two substituents together form an alicyclic radical);

(2) substituted hydrocarbon substituents, that is, substituents containing non-hydrocarbon groups which, in the context of this invention, do not alter the predominantly hydrocarbon substituent (e.g., halo (especially chloro and fluoro), hydroxy, alkoxy, mercapto, alkylmercapto, nitro, nitroso, and sulfoxy);

(3) hetero substituents, that is, substituents which, while having a predominantly hydrocarbon character, in the context of this invention, contain other than carbon in a ring or chain otherwise composed of carbon atoms. Heteroatoms include sulfur, oxygen, nitrogen, and encompass substituents as pyridyl, furyl, thienyl and imidazolyl. In general, no more than two, for example no more than one, non-hydrocarbon substituent will be present for every ten carbon atoms in the hydrocarbyl group; typically, there will be no non-hydrocarbon substituents in the hydrocarbyl group.

As used herein, the term “percent by weight”, unless expressly stated otherwise, means the percentage the recited component represents to the weight of the entire composition.

The composition disclosed herein can provide both temperature roll over effect and a passing High Temperature L-37 score. As used herein, “temperature roll over effect” refers to the effect a fluid exhibits in the Wind Tunnel Procedure when the difference (T_(roll over)) between the high fluid temperature (T_(MAX)) and the end-of-test temperature (T_(EOT)) is about 27° F. or more. As used herein, a “passing High Temperature L-37 score” refers to the result that a test machine achieves under testing conditions in a High Temperature L-37 test. The results of this test are measured on a scale of 0 to 10 where lower numbers reflect more heavy or severe wear and fatigue in the gear sets and higher numbers reflect little or no wear or fatigue.

The composition can be a lubricant composition for use in machines, such as light duty axles and stationary gearboxes. It is believed that the disclosed composition can provide at least one of the above-described properties when the machines are subjected to low and high temperatures and/or variable load conditions. In an aspect, the disclosed composition can be applied to, e.g., an axle that has not been broken-in for some time period or distance prior to towing. In another aspect, a light duty axle can be a hypoid gear axle. In yet another aspect, the disclosed composition can be applied to light duty cars, trucks and sport utility vehicles with or without limited slip mechanisms in the differential experience to improve at least gear wear protection. The lubricant composition can be suitably used with any friction material such as paper, steel, or carbon fiber. In still another aspect, the composition can be a top treat concentrate that is mixed/blended/combined with a base oil to formulate a lubricant composition for use in machines.

The disclosed compositions can comprise an anionic compound, and a cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifier. A friction modifier is understood to mean a compound comprising from about 10 to about 30 carbon atoms. In an aspect, the composition can comprise a friction modifying anionic compound and a cationic compound. In another aspect, the composition can comprise an anionic compound and a friction modifying cationic compound In a further aspect, the composition can comprise a friction modifying anionic compound and a friction modifying cationic compound.

The anionic compound for use in the disclosed composition can be at least one of a conjugate base of an organic carboxylic acid, organic phosphorus acid, organic sulfonic acid, inorganic phosphorus acid, and a mixture thereof. As used herein, a “conjugate base” is understood to mean a negatively charged ion that is formed when a Brønsted-Lowry acid loses a proton. In an aspect, the organic carboxylic acid can be linear or branched, saturated or unsaturated, and can comprise from about 5 to about 40, and for example from about 10 to about 30 carbon atoms. The organic carboxylic acid can be aliphatic. Non-limiting examples of the organic carboxylic acid include octenoic acid, isostearic acid, stearic acid, and mixtures thereof.

In an aspect, the anionic compound can be a conjugate base of an organic phosphorus acid, such as dialkyl phosphorus acid, monoalkyl phosphorus acid, dialkyl dithiophosphorus acid, monoalkyl dithiophosphorus acid, dialkyl thiophosphorus acid, monoalkyl thiophosphorus acid, and mixtures thereof. Other non-limiting examples of the organic phosphorus acid include amyl acid phosphate, diamyl acid phosphate, 2-ethylhexyl acid phosphate, di-2-ethylhexyl acid phosphate, dialkyl dithiophosphorus acid, and mixtures thereof.

Non-limiting examples of the dialkyl thiophosphorus acid include at least one of a compound of formulae (II) and (IV), shown below:

wherein n is an integer from about 1 to about 5; and

wherein R¹, R², R³, R⁴, R⁵, R⁶, R¹⁰, and R¹¹ can be independently selected from the group consisting of hydrogen, cyano, and hydrocarbyl groups comprising from about 1 to about 30 carbon atoms, for example from about 1 to about 20 carbon atoms, and as a further example from about 1 to about 10 carbon atoms.

In an embodiment, the anionic compounds can be present in a lubricating composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, for example from about 0.2 wt. % to about 0.6 wt. %, relative to the total weight of the composition. In another embodiment, the anionic compounds can be present in a top treat composition in an amount sufficient to yield a finished formulation consistent with the above-mentioned concentrations. Top treats typically contain much higher additive levels as compared to a finished formulation.

The cationic compound for use in the disclosed composition can be any cationic compound so long as it is soluble in a lubricating composition comprising a base oil. Non-limiting examples of the cationic compound include a conjugate acid of an amide, an amine, and a heterocyclic compound comprising a basic nitrogen, such as pyridine. As used herein, a “conjugate acid” is understood to mean a positively charged ion that is formed when a Brønsted-Lowry base gains a proton. In an aspect, the cationic compound is a conjugate acid of an amine, which can be primary, secondary, or tertiary.

The amines can have the general formula R′NH₂ wherein R′ can be a hydrocarbyl group containing up to about 150 carbon atoms and can be an aliphatic hydrocarbyl group containing from about 4 to about 30 carbon atoms.

In an aspect, the cationic compound can be conjugate acids of long chain primary, secondary and tertiary alkyl amines containing from about 12 to 30 carbon atoms, including their hydroxyalkyl and aminoalkyl derivatives. The long chain alkyl group may optionally contain one or more ether groups. Non-limiting examples of suitable cationic compounds include conjugate acids of oleyl amine, N-oleyltrimethylene diamine, N-tallow diethanolamine, N,N-dimethyl oleylamine and myristyloxapropyl amine.

In an aspect, the amines can be primary hydrocarbyl amines comprising from about 4 to about 30 carbon atoms in the hydrocarbyl group, and for example from about 8 to about 20 carbon atoms in the hydrocarbyl group. The hydrocarbyl group can be saturated or unsaturated. Representative examples of primary saturated amines are those known as aliphatic primary fatty amines. Typical fatty amines include alkyl amines such as n-hexylamine, n-octylamine, n-decylamine, n-dodecylamine, n-tetradecylamine, n-pentadecylamine, n-hexadecylamine, n-octadecylamine (stearyl amine), etc. These primary amines are available in both distilled and technical grades. While the distilled grade can provide a purer reaction product, amides and imides can form in reactions with the amines of technical grade. Also suitable are mixed fatty amines.

In an aspect, the cationic compound can be conjugate acids of tertiary-aliphatic primary amines having at least about 4 carbon atoms in the alkyl group. For the most part, they can be derived from alkyl amines having a total of less than about 35 carbon atoms in the alkyl group.

Usually the tertiary aliphatic primary amines are monoamines represented by the formula

wherein R¹, R², and R³ can be the same or different and can be a hydrocarbyl group containing from about one to about 30 carbon atoms. Such amines are illustrated by tertiary-butyl amine, tertiary-hexyl primary amine, 1-methyl-1-amino-cyclohexane, tertiary-octyl primary amine, tertiary-decyl primary amine, tertiary-dodecyl primary amine, tertiary-tetradecyl primary amine, tertiary-hexadecyl primary amine, tertiary-octadecyl primary amine, tertiary-tetracosanyl primary amine, tertiary-octacosanyl primary amine.

Conjugate acids of mixtures of amines are also useful for the purposes of this disclosure. Non-limiting examples of amine mixtures of this type can be a mixture of C₈-C₁₄ tertiary alkyl primary amines and a similar mixture of C₁₆-C₂₄ tertiary alkyl primary amines. The tertiary alkyl primary amines and methods for their preparation are well known to those of ordinary skill in the art and, therefore, further discussion is unnecessary.

Conjugate acids of primary amines in which the hydrocarbon chain comprises olefinic unsaturation also can be quite useful. Thus, the R groups can contain at least one olefinic unsaturation depending on the length of the chain, usually no more than one double bond per 10 carbon atoms. Representative compounds useful for purposes of this disclosure include conjugate acids of dodecenylamine, myristoleylamine, palmitoleylamine, oleylamine and linoleylamine.

Conjugate acids of secondary amines can also be useful. Examples of secondary amines include dialkylamines having two of the above alkyl groups including fatty secondary amines, and also mixed dialkylamines where R′ can be a fatty amine and R″ can be a lower alkyl group (1-9 carbon atoms) such as methyl, ethyl, n-propyl, i-propyl, butyl, etc., or R″ can be an alkyl group bearing other non-reactive or polar substituents (CN, alkyl, carboalkoxy, amide, ether, thioether, halo, sulfoxide, sulfone). The fatty polyamine diamines can include mono- or dialkyl, symmetrical or asymmetrical ethylene diamines, propane diamines (1,2, or 1,3), and polyamine analogs of the above. Suitable fatty polyamines include N-coco-1,3-diaminopropane, N-soyaalkyl trimethylenediamine, N-tallow-1,3-diaminopropane, and N-oleyl-1,3-diaminopropane.

In an embodiment, the cationic compounds can be present in a lubricating composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, for example from about 0.2 wt. % to about 0.6 wt. %, relative to the total weight of the composition. In another embodiment, the cationic compounds can be present in a top treat composition in an amount sufficient to yield a finished formulation consistent with the above-mentioned concentrations.

The anionic compound and the cationic compound can be reacted, mixed, blended, and/or combined so as to form a salt. The salts can be prepared by reacting, mixing, or combining the anionic compound and the cationic compound at room temperature (23° C.) or above for a period of from up to about one hour. The amount of cationic compound reacted with the anionic compound to form the salts of the disclosure is at least about one equivalent weight of the cationic compound per equivalent of anionic compound.

In an embodiment, the salt can be present in a lubricating composition in an amount ranging from about 0.1 wt. % to about 1.5 wt. %, relative to the total weight of the composition. In another embodiment, the salt can be present in a top treat composition in an amount sufficient to yield a finished formulation consistent with the above-mentioned concentrations.

In an aspect, the salt can comprise at least one of an amine salt of a phosphoric acid, an amine salt of a thiophosphoric acid, and an amine salt of dithiophosphoric acid. For example, a thiophosphoric acid can be reacted, mixed, blended and/or combined with at least one cationic compound to yield a salt, such as at least one of a compound of formulae (III) and (VI):

wherein n is an integer from 1 to 5; and

wherein R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, and R¹¹ can be independently selected from the group consisting of hydrogen, cyano, and hydrocarbyl groups comprising from about 1 to about 30 carbon atoms, for example from about 1 to about 20 carbon atoms, and as a further example from about 1 to about 10 carbon atoms. In an aspect, in formula (VI), R¹ and R² can be methyl; R³, R⁴, R⁵, R⁶, R⁷, and R⁸ can be hydrogen; R⁹ can be a tertiary C₁₂₋₁₄ alkyl group; and R¹⁰ and R¹¹ can be alkyl groups comprising from about 1 to about 6 carbon atoms. In an aspect, in formula (III), R³, R⁴, R⁵, R⁶, R⁷, and R⁸ can be hydrogen; R¹ and R² can be methyl; and R⁹ can be a tertiary C₁₂₋₁₄ alkyl group.

Methods for the preparation of such salts are well known and reported in the literature. See for example, U.S. Pat. Nos. 2,063,629; 2,224,695; 2,447,288; 2,616,905; 3,984,448; 4,431,552; 5,354,484; Pesin et al., Zhurnal Obshchei Khimii, 31(8): 2508-2515 (1961); and PCT International Application Publication No. WO 87/07638, the disclosures of which are hereby incorporated by reference.

The disclosed process can include the use of solvents. The solvent can be any inert fluid substance in which at least one of the reactants is soluble or the product is soluble. Non-limiting examples include benzene, toluene, xylene, n-hexane, cyclohexane, naphtha, diethyl ether carbitol, dibutyl ether dioxane, chlorobenzene, nitrobenzene, carbon tetrachloride, chloroform, base oil, such as gas-to-liquid and polyalphaolefin, and process oil.

Base oils suitable for use in formulating compositions according to the invention can be selected from any of the synthetic or natural oils or mixtures thereof. Natural oils include animal oils and vegetable oils (e.g., castor oil, lard oil) as well as mineral lubricating oils such as liquid petroleum oils and solvent treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic or mixed paraffinic-naphthenic types. Oils derived from coal or shale are also suitable. Further, oils derived from a gas-to-liquid process are also suitable.

The base oil can be present in a major amount, wherein major amount is understood to mean greater than or equal to 50%, for example from about 80 to about 98 percent by weight of the lubricant composition.

The base oil typically has a viscosity of, for example, from about 2 to about 15 cSt and, as a further example, from about 2 to about 10 cSt at 100° C. Thus, the base oils can normally have a viscosity in the range of about SAE 50 to about SAE 250, and more usually can range from about SAE 70W to about SAE 140. Suitable automotive oils also include cross-grades such as 75W-140, 80W-90, 85W-140, 85W-90, and the like.

Non-limiting examples of synthetic oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutylenes, polypropylenes, propylene isobutylene copolymers, etc.); polyalphaolefins such as poly(1-hexenes), poly-(1-octenes), poly(1-decenes), etc. and mixtures thereof; alkylbenzenes (e.g., dodecylbenzenes, tetradecylbenzenes, di-nonylbenzenes, di-(2-ethylhexyl)benzenes, etc.); polyphenyls (e.g., biphenyls, terphenyl, alkylated polyphenyls, etc.); alkylated diphenyl ethers and alkylated diphenyl sulfides and the derivatives, analogs and homologs thereof and the like.

Alkylene oxide polymers and interpolymers and derivatives thereof where the terminal hydroxyl groups have been modified by esterification, etherification, etc., constitute another class of known synthetic oils that can be used. Such oils are exemplified by the oils prepared through polymerization of ethylene oxide or propylene oxide, the alkyl and aryl ethers of these polyoxyalkylene polymers (e.g., methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or mono- and polycarboxylic esters thereof, for example, the acetic acid esters, mixed C₃₋₈ fatty acid esters, or the C₁₃ Oxo acid diester of tetraethylene glycol.

Another class of synthetic oils that can be used includes the esters of dicarboxylic acids (e.g., phthalic acid, succinic acid, alkyl succinic acids, alkenyl succinic acids, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid dimer, malonic acid, alkyl malonic acids, alkenyl malonic acids, etc.) with a variety of alcohols (e.g., butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) Specific examples of these esters include dibutyl adipate, di(2-ethylhexyl)sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, dieicosyl sebacate, the 2-ethylhexyl diester of linoleic acid dimer, the complex ester formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid and the like.

Esters useful as synthetic oils also include those made from C₅₋₁₂ monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylol propane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc.

Hence, the base oil used which can be used to make the compositions as described herein can be selected from any of the base oils in Groups I-V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. Such base oil groups are as follows:

Group I contain less than 90% saturates and/or greater than 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group II contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 80 and less than 120; Group III contain greater than or equal to 90% saturates and less than or equal to 0.03% sulfur and have a viscosity index greater than or equal to 120; Group IV are polyalphaolefins (PAO); and Group V include all other basestocks not included in Group I, II, III or IV.

The test methods used in defining the above groups are ASTM D2007 for saturates; ASTM D2270 for viscosity index; and one of ASTM D2622, 4294, 4927 and 3120 for sulfur.

Group IV basestocks, i.e. polyalphaolefins (PAO) include hydrogenated oligomers of an alpha-olefin, the most important methods of oligomerisation being free radical processes, Ziegler catalysis, and cationic, Friedel-Crafts catalysis.

The polyalphaolefins typically have viscosities in the range of 2 to 100 cSt at 100° C., for example 4 to 8 cSt at 100° C. They can, for example, be oligomers of branched or straight chain alpha-olefins having from about 2 to about 30 carbon atoms, non-limiting examples include polypropenes, polyisobutenes, poly-1-butenes, poly-1-hexenes, poly-1-octenes and poly-1-decene. Included are homopolymers, interpolymers and mixtures.

Regarding the balance of the basestock referred to above, a “Group I basestock” also includes a Group I basestock with which basestock(s) from one or more other groups can be admixed, provided that the resulting admixture has characteristics falling within those specified above for Group I basestocks.

Exemplary basestocks include Group I basestocks and mixtures of Group II basestocks with Group I bright stock.

Basestocks suitable for use herein can be made using a variety of different processes including but not limited to distillation, solvent refining, hydrogen processing, oligomerisation, esterification, and re-refining.

The base oil can be an oil derived from Fischer-Tropsch synthesized hydrocarbons. Fischer-Tropsch synthesized hydrocarbons can be made from synthesis gas containing H₂ and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to be useful as the base oil. For example, the hydrocarbons can be hydroisomerized using processes disclosed in U.S. Pat. No. 6,103,099 or 6,180,575; hydrocracked and hydroisomerized using processes disclosed in U.S. Pat. No. 4,943,672 or 6,096,940; dewaxed using processes disclosed in U.S. Pat. No. 5,882,505; or hydroisomerized and dewaxed using processes disclosed in U.S. Pat. No. 6,013,171; 6,080,301; or 6,165,949.

Unrefined, refined and rerefined oils, either natural or synthetic (as well as mixtures of two or more of any of these) of the type disclosed hereinabove can be used in the base oils. Unrefined oils are those obtained directly from a natural or synthetic source without further purification treatment. For example, a shale oil obtained directly from retorting operations, a petroleum oil obtained directly from primary distillation or ester oil obtained directly from an esterification process and used without further treatment would be an unrefined oil. Refined oils are similar to the unrefined oils except they have been further treated in one or more purification steps to improve one or more properties. Many such purification techniques are known to those skilled in the art such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, etc. Rerefined oils are obtained by processes similar to those used to obtain refined oils applied to refined oils which have been already used in service. Such rerefined oils are also known as reclaimed or reprocessed oils and often are additionally processed by techniques directed to removal of spent additives, contaminants, and oil breakdown products.

Optionally, other components can be present in the lubricant composition or additive composition. Non-limiting examples of other components include antiwear agents, extreme pressure agents, diluents, defoamers, emulsifiers, demulsifiers, antirust agents, friction modifiers, dispersants, corrosion inhibitors, antioxidants, pour point depressants, viscosity index improvers, rust inhibitors, dyes and solvents. These components may be present in various amounts depending on the needs of the final product.

Also disclosed herein is a method of lubricating a machine, such as an automotive gear, a stationary gearbox (including an industrial gear), and/or an axle with the disclosed lubricating composition. There is also disclosed a method of making a composition comprising providing at least one anionic compound and at least one cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifying compound comprising from about 10 to about 30 carbon atoms, and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater in the Wind Tunnel Procedure, and (ii) a passing High Temperature L-37 score.

EXAMPLES

Several test fluids were formulated (as provided in Table 1) and submitted to the Wind Tunnel Procedure. The Wind Tunnel Procedure measures a fluid's ability to function at a lower operating temperature as compared to a reference fluid in a new drive axle under towing conditions.

TABLE 1 T_(roll over) High Temp Test Fluid Cation Anion (° F.) L37 Test Example A [(oleylamine)H]+ [(RO)₂PO₂]— 106 PASS Example B [(oleylamine)H]+ [(RO)₂PO₂]— 37 PASS Example C [(oleylamine)H]+ [(RO)₂PS₂]— 60 FAIL Example D [(oleylamine)H]+ [RCO₂]— 29 FAIL Reference NA NA 0 PASS Fluid

In the Wind Tunnel Procedure, a test rig was fitted with a new lubricated production hypoid axle equipped with a thermocouple. The power source for the test rig consisted of a gasoline-powered V-8 engine capable of maintaining test conditions. Two axle dynamometers provided sufficient torque absorbing capacity to maintain axle torque and speed conditions. Shafts provided connectivity to the dynamometer and the axle. The engine was coupled to the test unit through a clutch and manual transmission. A shaft with universal joints provided connectivity to the manual transmission to the axle. The test rig was equipped with an airflow source.

The axle was filled with a test fluid in accordance with the axle specification and application. The test was conducted using 1500 ft/min airflow, 2835 rpm pinion speed, and 204 lb-ft pinion torque for a duration of 90 minutes. Pinion speed, pinion torque, fluid temperature, air temperature, and airflow were monitored throughout the full duration of the test. T_(MAX) of the test fluid over the duration of the test was noted, as well as T_(EOT) of the test fluid. As demonstrated in FIG. 1, T_(roll over) was then calculated as the difference between T_(MAX) and T_(EOT). A fluid is considered not to have a temperature roll over effect when T_(roll over) is less than about 15° C.

The test fluids were also employed in gear sets which were evaluated under High Temperature L-37 test conditions. The High Temperature L-37 Test is a low speed/high torque axle test method variation under ASTM D 3121. The standardized ASTM D 3121 is run under the following conditions: wheel speed of 80 rpm, and wheel torque of 1742 ft-lbs., for a duration of 24 hours at 275° F. The High Temperature L-37 Test Variation is run under the following conditions: wheel speed of 80 rpm, and wheel torque of 1742 ft-lbs., for a duration of 16 hours at 325° F.

The High Temperature L-37 test measures wear in the axle set as well as the extent of surface fatigue exemplified by ridging and pitting in the axle sets after operation and is construed as a severe test that evaluates the performance of the test fluid in inhibiting gear set wear and fatigue. The results of this test are measured on a scale of 0 to 10 where lower numbers reflect more heavy or severe wear and fatigue in the gear sets and higher numbers reflect little or no wear or fatigue.

The Wind Tunnel Procedure and High Temperature L-37 test results summarized in Table 1 above demonstrate desirable characteristics of the present invention. For instance, Examples A and B, which were formulated using an oleylamine cation and acid phosphate anion, are considered to have a temperature roll over effect. T_(roll over) was 106° F. for Example A and 37° F. for Example B, both of which are well above 27° F. Examples A and B also demonstrated passing High Temperature L-37 scores.

However, although Example C (oleylamine cation/diothiophosphate anion) and Example D (oleylamine cation/oleic acid anion) each demonstrated T_(roll over) greater than 27° F. (such as 60° F. and 29° F., respectively), both Examples C and D failed to achieve passing High Temperature L-37 scores. Likewise, the reference fluid achieved a passing High Temperature L-37 score but failed to demonstrate a temperature roll over effect. Thus, only the test fluids prepared according to the present disclosure demonstrated both a temperature roll over effect and a passing High Temperature L-37 score.

For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural referents unless expressly and unequivocally limited to one referent. Thus, for example, reference to “an antioxidant” includes two or more different antioxidants. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items.

While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents that are or can be presently unforeseen can arise to applicants or others skilled in the art. Accordingly, the appended claims as filed and as they can be amended are intended to embrace all such alternatives, modifications variations, improvements, and substantial equivalents. 

1. A lubricant composition comprising: at least one anionic compound; and at least one cationic compound; wherein at least one of the anionic compound and the cationic compound is a friction modifier; and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater, and (ii) a passing High Temperature L-37 score.
 2. The composition of claim 1, wherein the composition comprises at least one friction modifying anionic compound comprising from about 10 to about 30 carbon atoms and at least one cationic compound.
 3. The composition of claim 1, wherein the composition comprises at least one anionic compound and at least one friction modifying cationic compound comprising from about 10 to about 30 carbon atoms.
 4. The composition of claim 1, wherein the composition comprises at least one friction modifying anionic compound comprising from about 10 to about 30 carbon atoms and at least one friction modifying cationic compound comprising from about 10 to about 30 carbon atoms.
 5. The composition of claim 1, wherein the wherein the anionic compound is present in the composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, relative to the total weight of the composition.
 6. The composition of claim 1, wherein the cationic compound is present in the composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, relative to the total weight of the composition.
 7. The composition of claim 1, wherein the anionic compound is selected from the group consisting of a conjugate base of an organic carboxylic acid, organic phosphorus acid, organic sulfonic acid, inorganic phosphorus acid, and mixtures thereof.
 8. The composition of claim 7, wherein the organic carboxylic acid is linear or branched, saturated or unsaturated, and comprises from about 10 to about 30 carbon atoms.
 9. The composition of claim 7, wherein the organic carboxylic acid is aliphatic.
 10. The composition of claim 7, wherein the organic phosphorus acid is selected from the group consisting of dialkyl phosphorus acid, monoalkyl phosphorus acid, dialkyl dithiophosphorus acid, dialkyl thiophosphorus acid, and mixtures thereof.
 11. The composition of claim 7, wherein the organic phosphorus acid is selected from the group consisting of amyl acid phosphate, diamyl phosphate, 2-ethylhexyl acid phosphate, di-2-ethylhexyl acid phosphate, dialkyl dithiophosphoric acid, and mixtures thereof.
 12. The composition of claim 1, wherein the anionic compound is selected from the group consisting of octenoic acid, oleic acid, isostearic acid, steric acid, and mixtures thereof.
 13. The composition of claim 1, wherein the cationic compound is selected from the group consisting of conjugate acids of primary, secondary, and tertiary amines.
 14. The composition of claim 13, wherein the amine is linear or branched, saturated or unsaturated and comprises from about 10 to about 30 carbon atoms.
 15. The composition of claim 13, wherein the amine is a tertiary alkyl primary amine and comprises from about 8 to about 24 carbon atoms.
 16. The composition of claim 13, wherein the amine is a primary amine comprising olefinic unsaturation.
 17. The composition of claim 1, wherein the composition is a top treat.
 18. The composition of claim 1, further comprising a base oil.
 19. The composition of claim 18, wherein the composition is a lubricant composition.
 20. The composition of claim 18, wherein the base oil is mineral, synthetic, and a mixture thereof.
 21. The composition of claim 18, wherein the base oil is a polyalphaolefin.
 22. The composition of claim 18, wherein the base oil is a partial mineral oil.
 23. The composition of claim 18, wherein the base oil is gas-to-liquid oil.
 24. The composition of claim 19, wherein the anionic compound and the cationic compound form a salt that is present in the lubricant composition in an amount ranging from about 0.1 wt. % to about 1.5 wt. % relative to the total weight of the lubricant composition.
 25. A method of making a composition comprising: providing at least one anionic compound and at least one cationic compound, wherein at least one of the anionic compound and the cationic compound is a friction modifying compound comprising from about 10 to about 30 carbon atoms, and wherein the composition has (i) a temperature roll over difference of about 27° F. or greater, and (ii) a passing High Temperature L-37 score.
 26. The method of claim 25, wherein the cationic compound is present in the composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, relative to the total weight of the composition.
 27. The method of claim 25, wherein the anionic compound is present in the composition in an amount ranging from about 0.05 wt. % to about 1.0 wt. %, relative to the total weight of the composition.
 28. A vehicle lubricated with the composition of claim 1 wherein the vehicle has a gear final drive ratio ranging from about 2.5:1 to about 6:1.
 29. The vehicle of claim 28, wherein the vehicle is one of a light duty car, truck, sport utility vehicle with limited slip mechanisms in the differential experience, and sport utility vehicle without limited slip mechanisms in the differential experience.
 30. A machine lubricated with a composition according to claim
 1. 31. The machine of claim 31, wherein the machine is an automotive gear.
 32. The machine of claim 31, wherein the machine is a hypoid gear.
 33. The machine of claim 31, wherein the machine is a bevel gear.
 34. A vehicle comprising a light duty axle lubricated with the composition of claim
 1. 